Clamping mechanisms are often used to secure covers to containers or to secure tank halves to one another. Certain of such clamping mechanisms are used for simple attachment tasks. Because significant separating forces are not encountered the related clamping mechanisms require only minimum strength. Other types of clamping mechanisms are required to be quite sturdy, e.g., those which retain shells of pressurized vessels in closely fitted engagement with one another.
One type of known clamping mechanism is used with tank shells or housings, each of which has an annular flange or lip fitted to a similar flange on the companion shell. Such flanges offer a significant area of sealing contact and are maintained in a clamped position by a plurality of bolts received through holes spaced about the flanges. While clamping mechanisms of this type are strong, a very significant amount of time is required to assembly the tank and to remove all bolts to separate the shells in the event such is required for service. If one is required to separate the shells more frequently for service, such as to replace a filter, the described construction becomes even more disadvantageous.
Other types of known clamping mechanisms are shown in German Offenlegungsschrift DE 31 08 442 A1, U.S. Pat. No. 4,674,650, U.K. Patent specification 896,695 and Italian Brevetto per Invenzione 597282. The clamping mechanisms shown in the foregoing documents tend to share certain disadvantages.
Each of them includes a hoop-like band which is conformably fitted to and engaged with the projecting rims of the two container portions or shells to be clamped. Over time, the bands tend to undesirably adhere to such rims. It is not uncommon to encounter a band which must be tapped about its circumference with a mallet in order to loosen it prior to removal. Another disadvantage lies in the fact that such clamping bands are often joined at their ends by a single bolt or other fastener. Inadvertent failure to securely tighten the bolt or inattention to a bolt weakened by rust or corrosion can result in a bolt failure.
Yet a further disadvantage is that some of the clamping mechanisms illustrated in the documents noted above are intended only for joining together a non-pressurized container and its cover, for example. Such mechanisms are poorly or only moderately well suited for clamping together tank shells which confine a pressurized medium within them.
An improved tank clamping mechanism which may be installed and removed quickly and easily, which may be adapted to provide multiple points of clamping force and which is suitable for use with tank shells having a pressurized medium confined therewithin would be an important advance in the art.